METHOD FOR REDUCING HYDROGEN CHLORIDE EMISSIONS FROM AN ASPHALT AIR-BLOWING PROCESS

In a method for reducing hydrogen chloride emissions from an asphalt blowing process, ferric chloride and/or ferrous chloride are added to the asphalt. A chemical modifier is also added to the asphalt. The asphalt is subjected to a blowing process which produces hydrogen chloride emissions. The addition of the chemical modifier reduces the hydrogen chloride emissions by at least 25 % compared to the same process without the addition of the chemical modifier. The addition of the ferric chloride and/or ferrous chloride provides beneficial effects such as increased blowing rate and increased final penetration of the asphalt. Preferably, the addition of the chemical modifie r does not significantly reduce these beneficial effects.